Qt-interest Archive, January 2003
Plugin architecture
Message 1 in thread
Not really a Qt specific question, just wondering if anyone knows much about
writing applications with a plugin architecture? I've been searching for some
articles on the subject, or a book, but I have had no luck. Have any of you?
Happy hacking,
Martin
Message 2 in thread
On Wed, 01 Jan 2003 23:56:10 +0000, Martin Galpin wrote:
> Not really a Qt specific question, just wondering if anyone knows much about
> writing applications with a plugin architecture? I've been searching for some
> articles on the subject, or a book, but I have had no luck. Have any of you?
>
> Happy hacking,
> Martin
Plugins are cool and very easy to impliment - but you did not state if you
are using Linux or Windblows. I'll assume Linux for the mo...
1) Creating a plugin:
#include <stdio.h>
using namespace std;
// plugin function
extern "C" int function()
{
fprintf( stderr, "K, Plugin working.\n" );
return 0;
}
compile using:
g++ -fPIC -c code.c ... This will create code.o.
then...
g++ -shared -Wl,-soname,plugin.so -o plugin.so code.o ... This will create
plugin.so, which is actual plugin. i.e. the plugin that your program will
load and execute.
2) Calling plugin
#include <stdio.h>
#include <dlfcn.h> // Need this for dl functions
int main() {
char *(*entry)(); // Pointer to function from Plugin
void * module; // Pointer to Plugin
// load the module (plugin.so), and resolve symbols now
module = dlopen( "plugin.so", RTLD_NOW );
if(!module) {
fprintf(stderr, "[error]: dlopen() failed while resolving symbols.\n" );
return -1;
}
// retrieve address of entry point (the plugin function - function())
entry = (char*(*)())dlsym(module, "function");
if( entry == NULL ) {
dlclose(module);
fprintf(stderr, "[error]: dlerror() failed while retrieving address.\n" );
return -1;
}
// Call Plugin function
entry();
return 0;
}
compile using:
g++ -o driver driver.c -ldl ... -ldl loads the necessary libraries
And that it!
Mike
Message 3 in thread
Also, if you want your code to work in Windows too ( as the code I wrote
will compile with QT obviously as it is C/C++ compatable :-) ), you can
use a dll wraper.
Later, Mike
Message 4 in thread
"Michael Cowan" <michael_cowan@phreaker.net> wrote:
> Also, if you want your code to work in Windows too ( as the code I wrote
> will compile with QT obviously as it is C/C++ compatable :-) ), you can
> use a dll wraper.
...like using QLibrary
